Hydrationen

Hydration, referenced here as hydrationen, is the process by which water molecules interact with another substance. In chemistry, hydration has two related meanings: the solvation of species by water, and chemical hydration reactions in which water adds to a substrate. In both cases water can influence structure, stability and reactivity.

In aqueous solutions, ionic hydration describes how water molecules surround and orient around dissolved ions. The result is a hydration shell that stabilizes the ion through electrostatic interactions and hydrogen bonding. The strength of hydration is described by the enthalpy of hydration and by the hydration number, which tends to be higher for small, highly charged ions. The precise arrangement of water around an ion depends on ion size, charge density and temperature.

Chemical hydration refers to reactions where water adds across a bond or participates in bond-forming processes. Classically, the acid-catalyzed hydration of alkenes converts a carbon–carbon double bond into an alcohol by adding H and OH across the bond. Hydration can also describe related processes such as the hydration of alkynes or the hydrolysis of chemical bonds, where water contributes to bond cleavage and product formation. In biological systems, hydrolysis and hydration reactions underpin many metabolic pathways.

Industrial and material contexts include cement hydration, where water reacts with cement components to form hydrated compounds that impart strength. In biochemistry, hydration states influence protein folding, enzyme activity and molecular stability, making water a fundamental component of living systems. Hydration is thus a broad concept linking solvation, reaction chemistry and biological function.